/**
 * Copyright 2020 jianggujin (www.jianggujin.com).
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.jianggujin.modulelink.support.inject;

import java.lang.reflect.Field;

import com.jianggujin.modulelink.exception.JInjectException;
import com.jianggujin.modulelink.module.JModule;
import com.jianggujin.modulelink.support.JBeanProvider;
import com.jianggujin.modulelink.util.JModuleUtils;

/**
 * 自动注入抽象实现
 * 
 * @author jianggujin
 *
 */
public abstract class JAbstractInject implements JInject {
    protected final Object target;
    protected final Field field;
    protected final com.jianggujin.modulelink.support.annotation.JInject inject;

    public JAbstractInject(Object target, Field field, com.jianggujin.modulelink.support.annotation.JInject inject) {
        this.target = target;
        this.field = field;
        this.inject = inject;
    }

    @Override
    public void inject(JBeanProvider provider, JModule<?> module) throws Exception {
        Object value = this.handleValue(provider, module);
        if (value == null) {
            if (inject.required()) {
                throw new JInjectException("required [" + field.getName() + "] value must not be null");
            }
        } else {
            // 不为null师注入
            JModuleUtils.inject(field, target, value);
        }
    }

    /**
     * 处理需要注入的数据
     * 
     * @param provider
     * @param module
     * @return
     * @throws Exception
     */
    protected abstract Object handleValue(JBeanProvider provider, JModule<?> module) throws Exception;
}
